Vacuum-tube socket and contact terminals therefor



June 17, 1930.

MALDEN VACUUM TUBE SOCKET AND CONTACT TERMINALS THEREFOR Filed Dec. 19, 1924 Patented June 17, 1930 ourrao STATES PATENT oFFicE MILTON ALDEN, OF SPRINGFIELD, MASSACHUSETTS, ASSIGNOR TO THE ALDEN MANU- FAOTURING COMPANY, OF BROCKTON, MASSACHUSETTS, A. CORPORATION OF MAS- SACH'USETTS VACUUM-TUBE SOCKET AND OONTACT TERMINALS THEREFOR Application filed necember '19, .1924. Serial a. 756,904. 1

This invention relates to vacuum tube sockets and contact terminals therefor, particularly adapted for use in connection with wireless or radio apparatuses.

The objects of the invention areas follows 1st. To produce a vacuum tube socket and contact terminals therefor so constructed and arranged that when: the vacuum tube is being inserted in a socket, it will first be necessary to move the same downwardly until the contact pins projecting downwardly from the bottom of the vacuum tube will of the pins will slide along the upper surface of the contact plates and the sides thereof will be brought into engagement with the inner terminal edges of ears upon the inner ends of the contact plates and disposed at an acute angle to the upper face of the body portion thereof, thereby causing a wiping "contact to take place between the lower ends of the vacuum tube pins and the upper faces of'the contact plates, and also a wiping contact to take place between the inner terminal edges of the ears on said contact plates and the sides of the vacuum tube pins wherebycorrosion on the ends or sides of the pins where they contact with the plates will be removed. Upon releasing the pressure upon the vacuum tube, the resilient plates will cause it to move upwardly and the pins will then have a sliding contact with the inner terminal edges of the contact plate ears, and

thus a combined'wiping and sliding contact will be obtained between the contact plates and the vacuum tube pins.

2d. A very important objectof this invention is to secure perfect electrical connection between the contact plates and their respective bus wires and this is obtained mechanically by constructing the contact plateso that it will not only form a perfect con- I nection with the vacuum tube pins but also will 'enablethe bus wires to be connected thereto so as to form a rigid and integral part thereof, instead of connecting the bus wires to the contact plates by clamping them to the binding posts, and thus indirectly connecting them to the contact the binding posts.

To these ends the invention consists in an improved vacuum tube socket and in improved contact terminals therefor, all as set forth in the following specification, and particularly pointed out in the claims thereof.

Referring to the drawings: Figure l is a plan view of my improved socket. with the contact plates of my invention positioned thereon, the same being shown in connection with the portion of a panel.

Fig. 2 is a front elevation of the same.

plates through Fig. 3 is a sectional elevation taken on line 3 -3, Fig. 1, viewed in the direction of the arrows on said line.

Fig. 4 is an underneath and contact .plat'es. g

Fig. 5 is an enlarged detail sectional eleplan of the socket vation taken 'on' line 5- 5, Fig. 4.

Fig; 6 is an enlarged perspective View of one of the contact plates.

Fig. 7 is an enlarged plan view of the inner end portion of one of the contact plates, a vacuum tube pin being shown in section in the relation which it assumes thereto when the vacuum tube is first inserted in the socket.

Fig. 8 is a plan view similar to Fig. 7, illustrating one of :the acuum tube pins'in the position which it assumes relatively to the contact plate when the vacuum tube has been rotated to bring the side of the pin into engagement with the inner terminal edge of an ear'on the contact plate.

Fig. 9 is an end elevation of the contact plate and vacuum tube pin illustrated in Fig. 7.

'Fig. 10 is an end elevation of the contact plate-and a vacuum tube pin in the relative positions illustrated in Fig. 8.

Fig. 11 is a side elevation of a modified form of contact plate.

Fig. 12 is an underneath plan'of the base of a vacuum tube. l

Fig. 13is a side elevation of the same broken away to save space in. the drawings.

Like numerals refer to like parts throughout the several views of the drawings.

In the drawings, 15 is a vacuum tube socket consisting of a tubular portion 16 and ahollow cylindrical base 17. 18 is a portion of a panel to which the socket 15 is fastened by bolts 19. 20 is the base of a vacuum tube provided with four contact pins 21 extending downwardly therefrom, and a pin 22 projecting radially from the periphery thereof. Four contact plates 23 are fastened to the base 17 by bolts 24 and are held firmly in position upon the base not only by the bolts 24, but also by ribs located upon opposite sides thereof upon the under side of the base. These plates each consist of two leaves 25 and'26. 27 is the body portion of the contact late, and 28 is an ear extending upwardly tom the body portion and inclined inwardly over the body portion at an acute angle. The ear 28 terminates in a convexly curved inner edge 29. The body portion 27 of the contact plate is cut away at 30 adjacent to the ear 28. The outer end of the contact late terminates in an angle portion 31 consisting of a vertical side 32 and a horizontal side 33, the vertical side 32 being provided with a perforation 34. When the contact plate is positioned in the socket, the outer end thereof projects through an opening 35 provided in the base of the socket. 36' is a bus wire bent at its upper end to form an arm 37 which projects through an opening 35 in the base of the socket and through the hole 34 in the angle portion 31, the extreme end of the arm 37 lying upon the horizontal shelf or side 33 of the angle portion. The arm is fastened firmly to the angle portion of the contact plate by soldering or brazing, or in any suitable manner.

This form of bus wire is used where it is desired to conceal the wires leading from the contact plates to the connecting wires of the radio apparatus.

Another manner of connecting the-bus wire to the contact plate is shown in Fig. 3 atv the left, where a bus wire 36' extends horizontally or parallel to the face of the panel 18, and its inner end lies upon the shelf 33 and projects through the vertical side 32 of the angle portion 31 at the outer end of the contact plate. This inner end of the bus wire is soldered to the portion 33 of the contact plate. The tubular portion 16 of the socket is provided with a bayonet slot consisting of.

a main vertical part 38, an auxiliary vertical part 38' and a horizontally disposed part 39.

The operation of the device is as follows The base 20 of the vacuum tube is inserted in the bore of the tubular portion 16 of the socket with the radially extending pins 22 thereon entering the vertical portion 38 of the bayonet slot. The base of the tube is p then pushed downwardly into the socket until the pins 21 contact with the upper faces of the contact plates in the relative positions made of resilient or spring-like metal.

The next step in the process of inserting the tube in the socket is to rotate the vacuum tube in a clockwise direction, thus moving the pins from the relative location illustrated in Fig. 7 for example, to that shown in Fig. 8, and bringing the sides of the pins against the inner terminal edges of the ears 28.

Now the vacuum tube may be rocked forwardly and backwardly while the inner terminal edges of the ears 28 have an edge or line contact with the sides of the vacuum tube pins. A Wiping contact is thus obtained between the lower ends of the pins 21 and the upper faces 27 of the contact plates 23, and a wiping contact will also be obtained between the sides of the pins 21 and the inner terminal edges 29 of the ears 28. \Vhen the rocking motion has been performed sufficiently to'remove any traces of corrosion where the plates contact with the pins, the vacuum tube is released, and the pin 22 is carried up into the auxiliary portion 38 of the bayonet slot by the resiliency of the contact plates 23 which, it will be remembered, at this time are bent out of their normal positions. During this latter movement of the pins while in engagement with the ears 28 a sliding contact between the pins and the cars will be obtained, thus it will be seen that both a wiping and a sliding contact between the pins and the contact plates is secured when inserting the vacuum tube in the socket.

Preferably the contact plates are formed of two leaves 25 and 26, this construction giving a more resilient and flexible cont-act plate than a contact plate of one piece'would possess if made of the thickness of the two leaves 25 and 26.

It is evident, however, if preferred, the contact plate may be made of a single piece of spring metal, as illustrated in Fig. 11v in which 23' is the contact plate as a whole, 28 the ear and 31' the outer angle portion. It

plates. It will be understood that the contact plates are llU will be understood that the construction of any lateral movement and will also hold it in position against any vertical moven'lent by reason of the resilient contact plates pushing against the lower ends of the contact pins and holding the radially extending pin of the vacuum tube in the auxiliary portion 38 of the bayonet slot.

It will be seen from the foregoing specification that the bus wires or connecting wires may be easily, conveniently and firmly soldered to the contact plates, either when the socket is mounted on a panel or baseboard, and the bus wires are visible as illustrated by the bus wire 36, Fig. 3, or when the socket is screwed to a panel and the bus wires are l'n'ought up from below as in the case of the bus wire 36, Fig. 3, thus making assembly easy and convenient with all connecting wires concealed.

It is quite desirable to employ this latter method of connecting the bus wires to the contact plates, and thus keeping all connecting wires to the socket concealed. The usual method of accomplishing this end is to re verse the binding posts, such as 24, in the socket so that they slip down through and below the panel, butthe objection to this construction is that it requires a reassembling of the socket or a special assembling to meet the requirements. The socket of this invention will not only meet these requirements, but those of the regular mounting where the bus wires are visible. 7

By the construction of the contact plate hereinbefore set forth, it is possible to connect the bus Wire directly to the contact plate instead of indirectly connecting the bus Wire to the contact plate through the binding post. The hole 34 in the angular portion of the outer end of the contact plate of this invention makes it possible to fit either a round wire or a square bus wire, which is generally used, in the said hole, thus holding the wire in place resting on the shelf 33 while soldering flux is added, and thereby securing a quick, dependable assembly job.

Another advantage secured by the construction of the contact plate as to the angle portion 31 is that it may be brought down close to the outer periphery of the" base and" thus is not necessary to extend this portion of the contact plate unduly from the socket so as to be in the way and present an unsightly appearance where the socket is to be used with the regular binding screws- \Vhile the outer angular portion of the contact plate has been illustrated and hereinbefore described as ending at its inner end in an ear, it is evident that the same outer angular portion can be used on an ordinary contact plate consisting of a flat plate Without any ear at the inner end without departing from the spirit of my invention.

The contact terminals of this invention are an improvement upon the contact terminals disclosed in another application filed by me on June 8, 1922, Serial No. 566,893, and entitled Contact terminals for vacuum tubes.

Iclairn:

1. A socket comprising an insulating body having a supporting base flange and means for receiving a vacuum tube and conducting strips secured to said body, each strip having a spring contact portion for engaging a prong of the tube and having a portion integral therewith extending outwardly through the base flange and bent to have a solder-receiving groove and having a wire passage in one wall of said groove.

2. A contact plate for tube sockets comprising a' body portion, the outer end of said body portion terminating in an offset angle portion provided with an orifice to receive and position one end'of a wire, and an ear projecting from one side of said contact plate adjacent the opposite end thereof and positioned at an angle to one face of the body portion thereof.

3. A contact plate for tube sockets comprising a body portion and an ear adjacent the inner end of said contact plate and positioned at an acute angle to one face of the body portion thereof, the inner terminal edge of said ear being convexly curved and providin a sharp cutting edge.

4. K socket having an opening to receive a vacuum tube havingcontact pins'thereon, a plurality of contact plates on said socketextending into said opening, an car on each of said plates adjacent the inner end thereof and positioned at an acute angle to one face of the body portion thereof, said ears having sharp cutting terminal edges disposed in the path of rotation of the tube for engagement of their inner terminal edges with the sides of the contact pins when the tube is turned in the socket.

' 5. A socket having an opening to-receive a vacuum tube having contact plns thereon, and a laterally projecting pin on the eriphery thereof and adapted to enter a ayonet slot in said socket adjacent said opening, co

tact plates on said socket extending into sal d opening, an ear on each of said plates ads jacent the inner end thereof and positioned at an acute angle to one face of the body portion thereof each ear having a sharp cutting terminal edge, the ears being so positioned relatively to said bayonet slot that when the tube is inserted in the socket, the ends of its contact pins will firstengage the body portion of the contact plates, and then upon turning the tube, the sides of the pins will be brought into engagement with the inner terminal edges of the ears.

6. A contact plate for tube sockets comprising a body portion and an ear adjacent the inner end of said contact plate and positioned at an acute angle to one face of the body portion thereof the inner terminal edge of said ear having a sharp cutting edge so positioned that it will form a line contact with the side of a pin in contact therewith and positioned normal to said face.

7. A sheet metal contact member for a tube socket comprising a spring arm portion having a contact tip at its inner end for engaging the prong of a tube, said spring arm portion having its outer end offset to provide a solder-receiving recess, and having a wire passage in one wall thereof, said member having an anchorage portion between the spring arm portion and said offset outer end.

8. A socket for vacuum tubes comprising an insulating base having means for positioning a vacuum tube base having four prongs, and four contact members aving resilient portions projecting in w a r d l y through apertures in said base, and each provided with at least two yielding contact portions for one of the tube prongs one of said cont-act portions being vieldable lon 'tudinally of the socket and the other portlon bein yieldable laterally.

n testimony whereof I have hereunto set m hand.

y MILTON ALDEN. 

